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FI       DENT      OSIUM
                YMPO   M


        Date: 24th Fe     y
                    ebruary 2009
            ST minar Ha
          CS Sem           all

      e     Sustainable T
 Centre for S            Technoologies
      ndian I
     In                   Science
             Institute of S     e
            ngalore 560 0
          Ban       e     012
               First CST Student’s Symposium 2009 
                         Venue: CST Seminar Hall 
                            Date: 24­02­2009 

   Time                                        Programme 
14:30‐14:35  Introduction 

14:35‐14:45  Chairman’s Address  
               Reuse of waste materials for sustainable future 
               K. Asha, PhD Student 
             Experiments and modeling studies of turbo charged producer gas 
15:00‐15:15  based spark‐ignited reciprocating engines 
             Anand M. Shivapuji, PhD Student 
               Sustainability and nutrient lockup in Varthur Lake, Bangalore 
               Durga Madhab Mahapatra, M.Sc. (Engg) Student 
               Experimental analysis of reaction front propagation in a packed bed 
               Sadhan Mahapatra, PhD student 

15:45‐16:00                                    Tea Break 

               Hydrogen production through biomass gasification 
               Sandeep Kumar, M.Sc. (Engg) Student 
             Characterisation of environmental solids 
             Siva Chidambaram, PhD Student 
             Industrial and mine solid wastes for structural concrete and mortars 
             Ullas S.N., PhD Student 
             Spatio temporal pattern classifiers 
             Uttam Kumar, PhD Student 

17:00‐17:15  Feedback and discussions 

                Reuse of waste materials for sustainable future

                                         K.Asha, PhD student

                                  Centre for Sustainable Technologies
                             Indian Institute of Science, Bangalore 560 012

Enormous amounts of solid wastes are generated every year in the country. These waste materials
can be classified into four major categories, 1) municipal waste, 2) industrial waste, 3) hazardous
waste and 4) low level radioactive waste. Most of these materials have been land filled at considerable
cost since the inception of modern environmental regulations in the late 1970s and early 1980s.
Recently there has been a shift in societal attitudes resulting in strong interest in sustainability and
therefore developing beneficial re-use markets for industrial by-products. As a result, environmental
regulations have changed and beneficial re-use of industrial by-products are becoming now
permissible in a variety of applications. Development of industrial byproducts, from waste materials for
use in various applications will be examined in terms of

         - Engineering properties,
         - Innovative applications,
         - Environmental suitability,
         - Regulatory issues.

Waste products such as fly ash and phosphogypsum are produced in industrial processes.
Phosphogypsum is generated as a solid by-product in the "wet process" for the production of
phosphoric acid. Phosphogypsum by-products are chiefly composed of calcium sulfate. Additionally
they contain silica, alumina, iron oxides, phosphorous oxides and fluorides. Calcium sulfate the main
constituent of phosphogypsum wastes Worldwide, four methods are being used by the phosphate
industry to dispose of surplus phosphogypsum, namely: (i) discharging to water bodies; (ii) backfilling
in mine pits; (iii) dry stacking; and (iv) wet stacking.

Fly ash is produced by burning coal in thermal power stations Fly ash is disposed off using either dry
or wet disposal scheme. In dry disposal, the fly ash is transported by truck, chute or conveyor at the
site and disposed by constructing a dry embankment (dyke) that causes air-pollution in the
neighboring environment. In wet disposal, the fly ash is transported as slurry through pipe and
disposed off in impoundment called "ash pond". Most of the power plants in India use wet disposal
system, and when the lagoons are full, four basic options are available: (a) constructing new lagoons
using conventional constructional material, (b) hauling of fly ash from the existing lagoons to another
disposal site, (c) raising the existing dyke using conventional constructional material, and (d) raising
the dyke using fly ash excavated from the lagoon ("ash dyke"). Seepage from fly ash ponds
contaminates the surface and groundwater resources.

Disposal of phosphogypsum and fly ash in landfills is no longer considered a sustainable option owing
to restrictions on availability of land for construction of landfills. To solve the problems of air and water
pollution from non-engineered disposal and minimize their disposal in landfills, a sustainable
alternative is to re-use these industrial by-products.

Fly ash recycling includes usage in Portland cement and grout , Embankments and structural fill ,
Waste stabilization and solidification , Raw feed for cement clinkers , Mine reclamation , stabilization of
soft soils , Road sub base , Aggregate. Phosphogypsum can be reused as road pavement ,Soil
conditioner, Cover for landfills , roof tiles , artificial reefs & oyster beds. Fly ash and phosphogypsum
together contribute as excellent binding material which can be used in several civil engineering

First CST Student’s Symposium 2009                                                                  Page 1 
Experiments and Modeling Studies of Turbo Charged Producer Gas
          based Spark-Ignited Reciprocating Engines

                               Anand M Shivapuji, PhD student

                                 Centre for Sustainable Technologies
                            Indian Institute of Science, Bangalore 560 012


Modeling of internal combustion engine and subsequent validation of the model remains one of the
most challenging fields of engineering. The difficulty arises primarily owing to the rather poor
understanding of the exact mechanism of heat release under rapidly changing conditions within the
engine cylinder. The work sought to be taken up will primarily focus on the operation of a turbo
charged, multi-cylinder spark ignited engine operating on producer gas. A mathematical model
simulating the performance of an SI engine under turbo charged condition is sought to be constructed.
The mathematical model seeks to build upon the 0-D model for naturally aspirated engines from a
previous work and incorporate appropriate corrections into the 0-D model to make it go in tune with the
experimental results. Stretching of the flame due to squish/reverse squish near MBT for high
compression ratio and subsequent alteration in the heat release rate is sought to be brought into the
0-D model. In line with the mathematic model for the internal combustion engine, a similar
mathematical model for the turbo charger is sought to be developed and validated. The modified 0-D
model for the naturally aspirated engine is sought to be extended to turbo charged system by coupling
the turbo charger model with the 0-D model for the IC engine. Turbulent flow parameters as required
by the mathematical models for both the IC engine and the turbo charger are to be acquired by flow
simulation within the system using computational fluid dynamics package. One of the previous
computational fluid dynamics based simulating of SI engine with producer gas as the fuel considering
arbitrary length scale for turbulence throws up some deviations from the experimental results. An
attempt is sought to be made to bring about appropriate length scale to reduce this deviation.

The mathematical model so developed are sought to be validated by conducting experiments on turbo
charged spark ignited internal combustion engine operating on producer gas.

First CST Student’s Symposium 2009                                                             Page 2 
    Sustainability and Nutrient lock up in Varthur Lake, Bangalore

                      Durga Madhab Mahapatra, MSc (Engg) Student

                                   Centre for Sustainable Technologies
                                  Indian Institute of Science, Bangalore


Nutrients such as C, N and P play a vital role in the growth and development of several micro and
macro organisms. The wetland systems such as Varthur Lake in Bangalore, as a man-made system,
at first creates a good water balance in the neighborhood and also act as sink for the pollutants from
anthropogenic sources. In peninsular India, it has been traditional to hold runoff rainwater in manmade
water bodies called tanks or lakes for later use especially during the dry periods. Greater dependence
on ground water has exhausted ground water supplies and will need to return to surface waters where
these above lakes are important. With increased urbanization, these water bodies are increasingly
receiving sewage as a secondary water and are reaching levels of nutrients well above safe limits and
often become eutrophied. As catchments have dwindled, sustainable use of these water bodies
dictates that in future there will be a need to sustain such water bodies in the vicinity of urban and peri-
urban areas with the use of both, surface run off during rainy season as well as sewage to meet the
short fall. Varthur Lake has been examined in this perspective.

Varthur Lake has received sewage for over 50 years and today receives about 40% of sewage
discharge from the city of Bangalore. Sewage brings in large quantities of C, N and P. As the lake
also functions as a treatment lagoon, a predominant anaerobic decomposition in the upper reaches of
the lake reduces oxygen in the water to 0 mg/L and also brings in some extent of anaerobic sludge.
As it flows towards the outlet with about 5 to 7 day hydraulic retention time, it begins to be aerated and
a second type of sludge is formed and settles closer to the outlets. In this study, sludge characterized
has been studied at the lake bottom as a function of the residence time and it shows interesting
trends. The tank has been heavily silted and as a result the water storage is quite low compared to its
original capacity. Much of the sludge collected at various points in the lake is significantly organic.
The quality of the sludge improves as it nears the outlet. The water quality is seen to pass criteria of a
conventional treatment system and is therefore the tank may be considered to perform a useful
function. This paper presents the results of sludge found at various locations as well as water quality
and brings out the possible threat to sustainability.

First CST Student’s Symposium 2009                                                                 Page 3 
Experimental analysis of reaction front propagation in a packed bed
                               Sadhan Mahapatra, PhD Student
                                 Centre for Sustainable Technologies
                            Indian Institute of Science, Bangalore 560 012


   Literature survey in the field of combustion and gasification in packed bed reactor of any solid fuel
   indicates that sufficient work has done in the area of furnaces, but only modest work in gasification
   route. Most of the work done under gasification has dealt with aspects such as effect of air mass
   flux on temperature profile in packed bed and effect of biomass feed rate, air-fuel ratio,
   composition and quality of producer gas composition and overall efficiency of the systems.
   Investigation into the combustion flame front propagation in packed bed gasifier has limited to
   charcoal, coke and very few investigations to biomass wood. Very few attempts have been made
   to study the same using different biomass fuel at different physical conditions. The present work
   tries to look into the reaction front propagation at different superficial air mass flux in two different
   packed beds.

   Experiments are conducted on a small experimental reactor (3kh/hr). This set up is used to
   measure the propagation rate in a packed bed of wood particles. The reactor is of 103 mm
   diameter and 1000 mm height and insulated with ceramic wool throughout the length to reduce the
   heat loss from the reactor. The biomass (casurina) samples are 17x13x10mm and moisture
   content 3-4%. Different profiles indicate temperature at different locations in the reactor as
   function of time. Based on this information, the rate of movement of thermal profile or the
   propagation rate can be obtained. The front movement varies with the mass flux. The flame front
   propagation rate is increases initially, attains a peak and then decreases with increase in mass
   flux. The same experiment also conducted in a field gasifier of 35 kg/hr rating with reactor
   diameter 350mm. The biomass (casurina) samples are cylindrical shape (30 mm long, average
   diameter 30 mm) and the moisture content 10-15%. In this case also, the propagation rate
   increases initially, attains a peak and then decreases to zero at higher mass flux.

   The peak reaction front propagation rates are almost same (0.0814 mm/sec in 3kg/hr and 0.0806
   mm/sec in 35 kg/hr) in both the cases. However the peak has shifted in 3kg/hr gasifier towards
   higher air mass flux. This is may be due to less moisture content in 3 kg/hr gasifier (3-4%) in
   compare to 35 kg/hr gasifier (10-15%), different particle size and also the heat loss is less in
   3kg/hr gasifier due to better insulation. Since the rate of increase of air mass flux is more than the
   rate of increase of front propagation rate, the peak temperature of the front increases with air
   mass flux. This aided by the increase of heat and mass transfer coefficients between the particle
   and gas. The front propagation rate initially increases and then decreases indicate the balance of
   the heat and mass transfer limitations during the process and at higher mass flux, the convective
   cooling is dominant. The understandings of the reaction front movement under different varying
   bed parameters establish the operation conditions of the gasifier.

First CST Student’s Symposium 2009                                                                 Page 4 
            Hydrogen production through Biomass gasification

                                Sandeep K, MSc (Engg) Student

                                  Centre for Sustainable Technologies
                             Indian Institute of Science, Bangalore 560 012

Hydrogen production over 96% is done through steam reformation or gasification of fossil fuels
currently. However, these methods are not sustainable and environment friendly. Biomass can be
used as a potential sustainable resource for hydrogen production through gasification process. The
gasification process essentially is the process of converting biomass to a gas called producer gas
through oxidation and reduction process. The complex thermo-chemical process converts of solid
biomass to gaseous fuels. Depending upon the gasification medium the fraction of the gaseous
species made up combustible gases such as hydrogen (H2), carbon monoxide (CO), traces of
methane (CH4) and other hydrocarbons vary. Significant work on biomass gasification using air as the
medium generates a gas with CO (16-22%), H2 (16-20%), CO2 (7-13%) and Nitrogen (45-50%). It also
contains a small percentage of methane (CH4), traces of soot (particulates) and tar.

Biomass contains 6% of hydrogen by weight in general. Apart from capturing this hydrogen in gaseous
form, using steam as a medium would enhance the conversion process. Steam not only acts as an
oxidizer and gasification agent but also contributes hydrogen into the syngas. Reaction of steam with
biomass is an endothermic process and oxygen is used to oxidize the fraction of biomass to eliminate
the nitrogen in the gas. Use of oxygen rather than air not only provide better thermal efficiency but also
maximizes the mole fraction of hydrogen which helps in easy and economical separation of hydrogen
from syngas. This process is called “Oxygen-Steam Gasification”.

Attempts to use Oxygen -steam gasification for hydrogen generation using different reactor
configuration is in progress. Use of a down draft reduces the complexity in the condensable that are
generated during gasification and improves the gas handling. Performance with different
Oxygen/Steam ratio and Steam/Biomass ratio has been studied. The effect of temperature and
residence time has also been studied. The current research at Indian Institute of Science is to use a
novel open top down draft gasification system for generating hydrogen rich gas. The gasification
medium is superheated steam and oxygen as oxidizing and gasifying agent. Experimental setup
includes scaled down downdraft gasifier in which oxygen is supplied from top and steam at around
8000C is injected in the oxidation/combustion zone. The paper addresses the results from the
equilibrium analysis and compares with the experiments. The different process parameters like
temperature profile, mass flux rate, oxygen/steam ratio and steam/biomass ratio is being studied.
System design, energy efficiency and processes for optimum hydrogen production will be presented.

First CST Student’s Symposium 2009                                                                Page 5 
                    Characterization of environmental solids

                              Sivachidambaram.S, PhD student

                                 Centre for Sustainable Technologies
                            Indian Institute of Science, Bangalore 560 012


Analysis of solid samples such like soils, river sediments, sewage sludge, natural and synthetic
adsorbents is more important towards understand the reactivity, chemical state and applicability of the
materials. For beginners in analytical sciences the following questions may rise: which method to be
followed and how the samples to be analyzed. Sophisticated instruments are available to analyze the
environmental solids. Understanding the principles of instruments & instrumentation helps to figure out
the suitable method to a particular analysis. The method validation is giving confidence to present the
data. This discussion deals with the effective usage (principal, instrumentation, application,
interpretations) of analytical instruments for characterizing the environmental solids.

The microwave enhanced digestion complete our total dissolution & partial dissolution or extraction
needs using near stoichiometric quantities of reagents. ICP-ES (Inductively coupled plasma emission
spectroscopy) is one of the easiest methods in quantitative elemental analysis. The knowledge about
samples and standards preparation, standards stability, acid matrix, chemical compatibility, equipment
settings, wavelength selection, physical chemical interferences, method validation are helpful to get
reliable results in the ICP-OES method. Ion-chromatography, a separation process which can be used
to measure anions as well as cations from the aqueous samples.

The synthetic materials which are prepared to limit the contaminations in the environment can be
analyzed in XRD (X-ray diffractometer), Infra red Spectroscopy, Thermal analysis, X-ray photoelectron
spectroscopy, electro kinetic measurements in order to determine the compound formation, reaction
mechanism, phase change, chemical state of interested element, charge and colloidal properties of
the materials. The latest improvements such like EPMA (electron microprobe analysis) is allow the
users to do non-destructive analysis.

First CST Student’s Symposium 2009                                                             Page 6 
Industrial and mine solid wastes for structural concrete and mortars

                                       Ullas S N., PhD student

                                  Centre for Sustainable Technologies


Construction industry is one of the fastest growing industries in India. It is the second largest industry
to provide employment, next to agriculture. Ever increasing population demands various construction
needs in large scale which consumes significant volume of natural resources and energy in alarming
rate. This has made construction industry to contribute about 22% of Green House Gas emissions in
to the atmosphere. Impact of this on environment in the form of global warming has become the
concern of the day for environmentalists, scientists and policy makers.

Concrete and mortar are of considerable volume in any structure and consumed in bulk quantities for
the construction of buildings, roads and other infrastructure projects. Sand as fine aggregates is one of
the basic ingredients in concrete and mortar. Sand is mined from river beds and streams.
Indiscriminate mining of river sand has serious adverse impact on environment and hence sand
mining has been controlled and even banned in many locations. This has resulted in acute shortage of
sand supply which has made sand as expensive construction material. In order to address this,
alternatives to river sand are being explored by manufacturing sand through crushing of rocks which is
highly energy intensive process. In some case, granite quarrying produces ‘quarry dust’ which is also
used as sand.

Utilization of mine and industrial solid wastes for building products and applications is an emerging
area. In the present study, Kuduremukh iron ore tailings is initially chosen for investigation of its
suitability as fine aggregates in concrete and mortars. The iron ore tailings is stored in Lakya dam,
which was specially built for the same purpose. Mining operations were carried by Kuduremukh Iron
Ore Company Limited (KIOCL) during 1980 to 2005. After extraction of ore, the tailings were pumped
into the Lakya dam. The quantity of tailings stored in the tank is to the tune of about 200 million
tonnes. If found suitable, this tailing can meet the sand demand of Bangalore city for 30-40 years
assuming the present consumption rate of sand in Bangalore city.

With this background, about 10 tonnes of tailings have been collected from various points of the
storage dam and transported and stored in the campus. Various physical and chemical analysis will be
carried out and testing is in progress to investigate primary characteristics of the tailings for its
suitability to be used as fine aggregates. Other tests on mortar and concrete will follow the present
investigation to understand the behavior of concrete and mortar with iron ore tailings as fine aggregate
both in green and hardened state.

First CST Student’s Symposium 2009                                                                Page 7 
                         Spatio temporal pattern classifiers

                                    Uttam Kumar, PhD student

                                 Centre for Sustainable Technologies
                               and Department of Management Studies
                            Indian Institute of Science, Bangalore 560 012


Temporal remote sensing (RS) data coupled with spatial analysis helps in monitoring the status and
extent of spatial features. The spectral signature associated in each pixel of the remotely sensed data
is used to perform the classification and, indeed, is used as the numerical basis for categorisation of
various spatial features. Most of these classifications are based on certain data mining techniques.
Among the various frameworks of data mining in which pattern classifiers have been traditionally
formulated, the statistical approach has been most intensively studied and used in practice involving:
definition of pattern classes, sensing environment, pattern representation, feature extraction and
selection, cluster analysis, classifier design and learning, selection of training and test samples, and
performance evaluation. We have attempted extraction of water bodies through pattern classifiers with
the temporal RS data.

Pattern classifiers were used to extract wetlands automatically from NIR bands of MODIS, Landsat
MSS and Landsat TM RS data. MODIS provided data for 2002 to 2007, while for 1973 and 1992 IR
Bands of Landsat MSS and TM (79m and 30m spatial resolution) data were used. Principal
components of IR bands of MODIS (250 m) were fused with IRS LISS-III NIR (23.5 m). Statistical
unsupervised learning of IR bands for the respective temporal data was performed using Bayesian
approach based on prior probability, mean and covariance for the number of user specified classes to
extract wetlands. The groups were then interpreted based on prior knowledge and field experience. In
this approach, where no previous estimation parameters were available, quite motivating and realistic
results were obtained in extracting water class and their extent. The analysis revealed that there were
51 wetlands (321 ha) in 1973, 38 (207 ha) in 1992, 25 (135 ha) in 2002 and dropped down to 17 with
an extent of 87 ha in 2007 in the Bangalore city limits attributing to intense urbanization processes.

First CST Student’s Symposium 2009                                                              Page 8 

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